The invention pertains to an element for washing or treating a yarn or similar structure with a fluid, the element comprising a cavity for guiding the yarn and at least one fluid jet for directing the fluid into the yarn.
Such a washing element is known from WO 93/06266, which describes how the exchange of mass and heat between a yarn and a washing fluid can be improved by jetting the fluid into the yarn. As a result of the enhanced exchange, the time needed for washing the yarn is reduced and the machinery involved can be smaller.
However, due to the use of the jet or jets and/or the high speeds of the yarn utilized in modern equipment, the washing fluid is disturbed to such an extent that the formation of a spray or aerosol of the washing fluid, which normally contains the substances that have been washed out of the yarn, is unavoidable. The aerosol seriously contaminates the working environment and the equipment itself. Especially when aggressive materials are involved, which is often the case, for instance in the production of aramid yarn (sulphuric acid) or cellulose yarn (phosphoric acid), the contamination poses a considerable threat to both personnel and equipment and makes it necessary to implement several expensive and impractical safety measures.
Another problem encountered during the washing or treating of yarns is the consumption of washing or treating fluid. A washing fluid containing, e.g., sulphuric acid removed from an aramid yarn usually needs further processing before it can be re-used or discharged, which always incurs additional costs. Therefore, the amount of fluid used in the washing or treating process should be as low as possible and the mass transfer to the fluid should be as effective as possible.